seems like a role of UN troops to maintain peace so that WHO workers can do their jobs
To provide some context, just the eastern provinces of the DRC, where most of the violence is concentrated, have a population of more than 20 million people and a land area larger than Germany. The UN mission in the DRC, MONUSCO, has just 15 000 troops. A figure which shrinks annually as a result of US-forced budget cuts.
Those budget cuts (which the Trump administration has loudly boasted about, FWIW) have also severely depleted the aviation budget, preventing MONUSCO from being able to deploy as many attack helicopters as its commanders say it needs to go after armed groups and reducing its ability to transport troops by air. This forces them to take long, slow journeys on the country's dilapidated road network, even in cases of urgent responses. During the rainy season it can take hours to travel a few kilometres despite having specialised vehicles.
Add to that the fact that government troops are often corrupt and local commanders can be in league with some of the rebel groups, and it's a pretty difficult mission at the best of times.